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  <script>
    const obj = { 
      name: 'zs',
      age: 18,
      info: {
        address: '北京',
        tel: 1888888888
      }
    }
    console.log(obj.infomation?.tel); // 短路 obj有infomation这个字段的话 要这个infomation中tel
    console.log(obj?.sex);
  </script>
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